This Competing Continuation application requests funding for Years 07 to 11 of the NIMH collaborative Multimodal Treatment Study of Children with Attention Deficit Hyperactivity disorder (MTA Study). In a parallel group design, 579 rigorously diagnosed children with ADHD age 7-9 were randomly assigned to four treatment conditions: (1) Medication-only ; (2)Psychosocial-only; (3) Combined (medication and psychosocial); (4) Assessment-and-Referral condition. All but the latter were treated intensively for 14 months, with assessments for all subjects at baseline, 3, 9, 14, and 24 months. The original MTA design thus provides short-term (10 months post-treatment) follow-up at 24 months. Additional funding during Year 06 supported the collection of a local Normative Comparison Group (LNCG) drawn from the same schools as ADHD children. This Continuation would extend the follow-up to assessments at 36-, 60-, and 84 months after treatment. Continuation Aim 1 is to track the persistence of intervention-related effects as the MTA sample matures into mid-adolescence, including subsequent mental-health and school-related service utilization patterns as a function of MTA treatment experience (treatment assignment) and outcome (degree of treatment success at 14 mo.). Aim 2 is to test specific hypotheses about predictors, mediators, and moderators of long-term outcome among children with ADHD (e.g., comorbidity; family functioning; cognitive skills; peer relations) that may influence adolescent functioning (either independently of or through initial treatment assignment and/or 14-month treatment outcomes); and to compare how these predictors, and moderators are similar or dissimilar within the LNCG. Aim 3 is to track the patterns of risk and protective factors (including their mediation or moderation by initial treatment assignment and/or outcome) involved in early and subsequent stages of developing substance-related disorders and antisocial behavior. Aim 4 is to examine the effect of initial treatment assignment and degree of treatment success on later academic performance, achievement, school conduct, tendency to drop out, and other adverse school outcomes.